This invention relates to a portable sprayer and is particularly concerned with a sprayer for treating an area with two different products in a single pass. The sprayer is particularly adapted for applying mosquito control products, although its use is not limited to this application.
The most effective treatment of an area for mosquito control results from the application of two products. The first product, known as a knockdown product or knockdown treatment, is designed to kill mosquitoes already in a treatment zone. It is most effective when applied as an ultra low volume (ULV) spray or fog with small, lightweight droplet sizes. The second product, known as a barrier product or barrier treatment, is designed to prevent mosquitoes from entering the treatment zone. It is best applied in larger, heavier droplet sizes that impinges on plants and foliage with a material that repels and/or kills mosquitoes. The difference in required droplet sizes for the knockdown product and barrier product dictates that two separate nozzles be used to distribute the two products. This has been done commercially with a variety of units, all having separate sprayers.
Some prior art ULV sprayers of this type are mounted on a truck and are engine-powered. Similarly, truck-mounted mist blowers having very large blasts of air are powered by gasoline engines. With these types of units mounted on trucks there is ample space to accommodate separate nozzles and ample power available to drive them. Such is not the case with sprayers intended for household or consumer use. Other prior art sprayers have ULV nozzles in a hand-held unit powered by a small gasoline engine or an electric motor using a power cord. There are also prior art barrier product sprayers that supply a liquid stream only. That is, there is no air mixed with the liquid. These are available for nursery and household use in both truck-mounted and hand-cart mounted units. They are powered both by gasoline engines and electric motors, including battery powered motors.
Household sprayers need to be portable, preferably hand-held units which do not require an electrical cord. Because of these limitations in portable units, the conventional practice in household sprayers has been to make two separate passes with two separate nozzles, one for applying the knockdown product and one for applying the barrier product. Obviously, this is not the most convenient arrangement since making two passes takes twice as long as making one pass. Also, with this conventional practice either two entirely separate sprayers must be used or a single sprayer must have its nozzle and product supply reservoir changed after the first pass. Neither of these arrangements is optimal.
Furthermore, it is desirable to use battery power for household sprayers because rechargeable batteries are more convenient to use compared to units powered by gasoline engines or household current, the latter requiring a long, unwieldy extension cord. While hand-held, battery-powered sprayers are preferable from a convenience standpoint, the batteries are limited in the amount of power they can supply so the sprayer must be designed to minimize power use and make changing the battery pack simple and quick. It has not previously been feasible to have a dual-output sprayer including a ULV nozzle in a hand-held, battery-powered unit.